From: Christian Koenig <christian.koenig@xxxxxxx>
The spinlock was actually there to protect the
rptr, but rptr was read outside of the locked area.
Also we don't really need a spinlock here, an
atomic should to quite fine since we only need to
prevent it from being reentrant.
v2: Keep the spinlock....
v3: Back to an atomic again after finding & fixing the real bug.
Signed-off-by: Christian Koenig <christian.koenig@xxxxxxx>
---
drivers/gpu/drm/radeon/evergreen.c | 26 +++++++++++++-------------
drivers/gpu/drm/radeon/r600.c | 29 +++++++++++++----------------
drivers/gpu/drm/radeon/radeon.h | 3 +--
drivers/gpu/drm/radeon/radeon_device.c | 3 +--
drivers/gpu/drm/radeon/si.c | 27 +++++++++++++--------------
5 files changed, 41 insertions(+), 47 deletions(-)
diff --git a/drivers/gpu/drm/radeon/evergreen.c b/drivers/gpu/drm/radeon/evergreen.c
index dd3cea4..18abe3c 100644
--- a/drivers/gpu/drm/radeon/evergreen.c
+++ b/drivers/gpu/drm/radeon/evergreen.c
@@ -2943,7 +2943,6 @@ int evergreen_irq_process(struct radeon_device *rdev)
u32 rptr;
u32 src_id, src_data;
u32 ring_index;
- unsigned long flags;
bool queue_hotplug = false;
bool queue_hdmi = false;
@@ -2951,22 +2950,21 @@ int evergreen_irq_process(struct radeon_device *rdev)
return IRQ_NONE;
wptr = evergreen_get_ih_wptr(rdev);
+
+restart_ih:
+ /* is somebody else already processing irqs? */
+ if (atomic_xchg(&rdev->ih.lock, 1))
+ return IRQ_NONE;
+
rptr = rdev->ih.rptr;
DRM_DEBUG("r600_irq_process start: rptr %d, wptr %d\n", rptr, wptr);
- spin_lock_irqsave(&rdev->ih.lock, flags);
- if (rptr == wptr) {
- spin_unlock_irqrestore(&rdev->ih.lock, flags);
- return IRQ_NONE;
- }
-restart_ih:
/* Order reading of wptr vs. reading of IH ring data */
rmb();
/* display interrupts */
evergreen_irq_ack(rdev);
- rdev->ih.wptr = wptr;
while (rptr != wptr) {
/* wptr/rptr are in bytes! */
ring_index = rptr / 4;
@@ -3265,17 +3263,19 @@ restart_ih:
rptr += 16;
rptr &= rdev->ih.ptr_mask;
}
- /* make sure wptr hasn't changed while processing */
- wptr = evergreen_get_ih_wptr(rdev);
- if (wptr != rdev->ih.wptr)
- goto restart_ih;
if (queue_hotplug)
schedule_work(&rdev->hotplug_work);
if (queue_hdmi)
schedule_work(&rdev->audio_work);
rdev->ih.rptr = rptr;
WREG32(IH_RB_RPTR, rdev->ih.rptr);
- spin_unlock_irqrestore(&rdev->ih.lock, flags);
+ atomic_set(&rdev->ih.lock, 0);
+
+ /* make sure wptr hasn't changed while processing */
+ wptr = evergreen_get_ih_wptr(rdev);
+ if (wptr != rptr)
+ goto restart_ih;
+
return IRQ_HANDLED;
}
diff --git a/drivers/gpu/drm/radeon/r600.c b/drivers/gpu/drm/radeon/r600.c
index a8d8c44..ffbf0b7 100644
--- a/drivers/gpu/drm/radeon/r600.c
+++ b/drivers/gpu/drm/radeon/r600.c
@@ -2921,7 +2921,6 @@ void r600_disable_interrupts(struct radeon_device *rdev)
WREG32(IH_RB_RPTR, 0);
WREG32(IH_RB_WPTR, 0);
rdev->ih.enabled = false;
- rdev->ih.wptr = 0;
rdev->ih.rptr = 0;
}
@@ -3373,7 +3372,6 @@ int r600_irq_process(struct radeon_device *rdev)
u32 rptr;
u32 src_id, src_data;
u32 ring_index;
- unsigned long flags;
bool queue_hotplug = false;
bool queue_hdmi = false;
@@ -3385,24 +3383,21 @@ int r600_irq_process(struct radeon_device *rdev)
RREG32(IH_RB_WPTR);
wptr = r600_get_ih_wptr(rdev);
- rptr = rdev->ih.rptr;
- DRM_DEBUG("r600_irq_process start: rptr %d, wptr %d\n", rptr, wptr);
-
- spin_lock_irqsave(&rdev->ih.lock, flags);
- if (rptr == wptr) {
- spin_unlock_irqrestore(&rdev->ih.lock, flags);
+restart_ih:
+ /* is somebody else already processing irqs? */
+ if (atomic_xchg(&rdev->ih.lock, 1))
return IRQ_NONE;
- }
-restart_ih:
+ rptr = rdev->ih.rptr;
+ DRM_DEBUG("r600_irq_process start: rptr %d, wptr %d\n", rptr, wptr);
+
/* Order reading of wptr vs. reading of IH ring data */
rmb();
/* display interrupts */
r600_irq_ack(rdev);
- rdev->ih.wptr = wptr;
while (rptr != wptr) {
/* wptr/rptr are in bytes! */
ring_index = rptr / 4;
@@ -3556,17 +3551,19 @@ restart_ih:
rptr += 16;
rptr &= rdev->ih.ptr_mask;
}
- /* make sure wptr hasn't changed while processing */
- wptr = r600_get_ih_wptr(rdev);
- if (wptr != rdev->ih.wptr)
- goto restart_ih;
if (queue_hotplug)
schedule_work(&rdev->hotplug_work);
if (queue_hdmi)
schedule_work(&rdev->audio_work);
rdev->ih.rptr = rptr;
WREG32(IH_RB_RPTR, rdev->ih.rptr);
- spin_unlock_irqrestore(&rdev->ih.lock, flags);
+ atomic_set(&rdev->ih.lock, 0);
+
+ /* make sure wptr hasn't changed while processing */
+ wptr = r600_get_ih_wptr(rdev);
+ if (wptr != rptr)
+ goto restart_ih;
+
return IRQ_HANDLED;
}
diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index e68db99..dfcba32 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -735,11 +735,10 @@ struct r600_ih {
struct radeon_bo *ring_obj;
volatile uint32_t *ring;
unsigned rptr;
- unsigned wptr;
unsigned ring_size;
uint64_t gpu_addr;
uint32_t ptr_mask;
- spinlock_t lock;
+ atomic_t lock;
bool enabled;
};
diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
index 7667184..3c563d1 100644
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -731,8 +731,7 @@ int radeon_device_init(struct radeon_device *rdev,
radeon_mutex_init(&rdev->cs_mutex);
mutex_init(&rdev->ring_lock);
mutex_init(&rdev->dc_hw_i2c_mutex);
- if (rdev->family >= CHIP_R600)
- spin_lock_init(&rdev->ih.lock);
+ atomic_set(&rdev->ih.lock, 0);
mutex_init(&rdev->gem.mutex);
mutex_init(&rdev->pm.mutex);
init_rwsem(&rdev->pm.mclk_lock);
diff --git a/drivers/gpu/drm/radeon/si.c b/drivers/gpu/drm/radeon/si.c
index 5ca8ef5..abd3b99 100644
--- a/drivers/gpu/drm/radeon/si.c
+++ b/drivers/gpu/drm/radeon/si.c
@@ -3095,7 +3095,6 @@ static void si_disable_interrupts(struct radeon_device *rdev)
WREG32(IH_RB_RPTR, 0);
WREG32(IH_RB_WPTR, 0);
rdev->ih.enabled = false;
- rdev->ih.wptr = 0;
rdev->ih.rptr = 0;
}
@@ -3512,29 +3511,27 @@ int si_irq_process(struct radeon_device *rdev)
u32 rptr;
u32 src_id, src_data, ring_id;
u32 ring_index;
- unsigned long flags;
bool queue_hotplug = false;
if (!rdev->ih.enabled || rdev->shutdown)
return IRQ_NONE;
wptr = si_get_ih_wptr(rdev);
+
+restart_ih:
+ /* is somebody else already processing irqs? */
+ if (atomic_xchg(&rdev->ih.lock, 1))
+ return IRQ_NONE;
+
rptr = rdev->ih.rptr;
DRM_DEBUG("si_irq_process start: rptr %d, wptr %d\n", rptr, wptr);
- spin_lock_irqsave(&rdev->ih.lock, flags);
- if (rptr == wptr) {
- spin_unlock_irqrestore(&rdev->ih.lock, flags);
- return IRQ_NONE;
- }
-restart_ih:
/* Order reading of wptr vs. reading of IH ring data */
rmb();
/* display interrupts */
si_irq_ack(rdev);
- rdev->ih.wptr = wptr;
while (rptr != wptr) {
/* wptr/rptr are in bytes! */
ring_index = rptr / 4;
@@ -3785,15 +3782,17 @@ restart_ih:
rptr += 16;
rptr &= rdev->ih.ptr_mask;
}
- /* make sure wptr hasn't changed while processing */
- wptr = si_get_ih_wptr(rdev);
- if (wptr != rdev->ih.wptr)
- goto restart_ih;
if (queue_hotplug)
schedule_work(&rdev->hotplug_work);
rdev->ih.rptr = rptr;
WREG32(IH_RB_RPTR, rdev->ih.rptr);
- spin_unlock_irqrestore(&rdev->ih.lock, flags);
+ atomic_set(&rdev->ih.lock, 0);
+
+ /* make sure wptr hasn't changed while processing */
+ wptr = si_get_ih_wptr(rdev);
+ if (wptr != rptr)
+ goto restart_ih;
+
return IRQ_HANDLED;
}
--
1.7.9.5
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